Bit boring extension rod



Nov. 2, 1965 w. H. VERNER BIT BORING EXTENSION ROD Filed Sept. 26, 1965 INVENTOR.

WILLIAM H. VERNER BY 2 UTORNt-IY United States Patent 3,215,444 BIT BORING EXTENSION ROD William H. Verner, 308 Spahr St., Pittsburgh 32, Pa. Filed Sept. 26, 1963, Ser. No. 311,840 1 Claim. (Cl. 279-36) This invention relates to improvements in a woodboring bit and, more particularly, to novel clamping jaw means for clamping an extension rod thereto.

An outstanding disadvantage of conventional types of woodboring bit clam-ping means for extension rods is that they are relatively complicated in construction and do not securely clamp the bit to the extension rod but permit the bit to pull out from the clamping means necessitating extremely tight screw threading, which will often strip threads and still not assure a tight hold on the woodboring bit.

An object of the present invention is to provide a novel woodboring bit and clamping means to attach an extension rod thereto, which will overcome the above-named disadvantages and which will provide an assembly consisting of relatively simple and inexpensive parts which assure tight clamping without undue screw threading of parts and which will prevent pulling out of the bit away from the extension clamping means even after long use.

Other objects and advantages will become more apparent from a study of the following description taken with the accompanying drawing wherein:

FIG. 1 is a plan view of an assembly including a woodboring bit and clamping means for attaching an extension thereto and embodying the principles of the present invention;

FIG. 2 is an enlarged, fragmentary, longitudinal, crosssectional view of the clamping means contained within parts 10 and 11 of FIG. 1;

FIG. 3 is a longitudinal, cross-sectional view of the clamping means taken at right angles to the longitudinal plane of FIG. 2;

FIG. 4 is a transverse, cross-sectional view taken along line 44 of FIG. 2;

FIG. 5 is a transverse, cross-sectional view taken along line 5-5 of FIG. 3;

FIGS. 6 and 7 are top and side views of one of the identical clamping jaws 8 shown in FIGS. 2. and 3;

FIG. 8 is a longitudinal view, partly in section, of a modification; and,

FIGS. 9 and 10 are side and top views of one of the clamping jaws 25 shown in FIG. 8.

Referring more particularly to FIG. 1, numeral 1 generally denotes a woodboring bit assembly comprising a drill or hit 2 for boring holes in wood (although it should be remembered that a metal-drilling bit may be used instead) and numeral 3 denotes the tapered end portion of the bit. An extension rod 4 is provided having a threaded end portion 5 which is integrally secured to a jaw retainer 6 having a somewhat U shape to provide a yoke whose inner faces 6a are tapered outwardly as shown in FIG. 3 to correspond to the taper of the end portion 3 of the bit. The legs of the U-defining part 6 are tapered outwardly, as shown at 7 in FIG. 2. A pair of mating jaws 8 are provided which are of identical construction and which are pivotally connected to a pin 9 which extends through holes formed in a flattened portion of reduced thickness 8a of the jaws, as illustrated in FIG. 7. The extremity of the jaw has a book which is arcuately shaped, as shown more clearly in FIG. 4, so as to closely hug the periphery of the bit 1.

As will appear more clearly in FIG. 3, portions 8a of the two cooperating jaws are stacked together so that the jaws pivot outwardly of the bit 1 but may be clamped thereto by the sleeve 10 when the nut 11 is screw threaded onto a threaded portion 5 of the extension rod 4.

If desired, a separate wedge shaped portion 14 may be screw threaded into the threaded end 13 of the extension rod 4 so that when the extension rod 4 is to be held in a drill press or electric drill, the end part 14 may be first removed to allow extension 4 to be clamped by the chuck of such press or drill.

In operation, when it is desired to attach bit 1 to the extension rod 4, the tapered end portion 3 of the rod is inserted between the legs of the U-shaped yoke 6, whereupon the arcuate surfaces 16 of the pair of jaws 8 will rest on opposed portions of the cylindrical or rod portion of the bit so that when the sleeve 10 is slipped snugly over the yoke 6 and the knurled nut 11 is turned and screw threaded onto the threaded portion 5, this will draw the jaws 8 inwardly of sleeve 10 so that the latter efl ects engagement with the outer surfaces of the jaws, as shown in FIG. 5, until they come within the confines of sleeve 10 and thus tightly grip the rod. The hooked ends near surfaces 16 prevent the bit from pulling apart since they closely embrace the base portion of the tapered end 3 and serve as a stop. In short, the inner tapered shaped surfaces 6a of yoke 6 will wedge against opposite wedge shaped surfaces of the tapered end portion 3 of the bit whereas the arcuate surfaces 16 at the end of jaws 8 are tightly clamped against the rod portion of the bit immediately adjacent the enlarged base portion of the tapered end which they closely embrace and thus securely hold the rod portion and prevent any possibility of pulling out or turning of the bit 2 in relation to the extension rod 4. The end portion 14 of rod 4, which may be either separately secured thereto, as shown, (or integral with the extension rod 4 if used in a brace), is then clamped in the jaws of the electric drill.

Of course, to detach the drill 2 from the extension rod it is merely necessary to unscrew the nut 11 and pivot jaws 8 outwardly, whereupon the end portion 3 of the drill may be pulled out of the clamping jaws.

FIGS. 8, 9 and 10 show a modification comprising an extension rod 29 having an end portion 24 screw threaded to a socket 23 within a jaw retaining sleeve 21 and knurled nut 28. Screw threads 22 threadedly engaging the interior of nut 28 to draw a pair of jaws 25 into jaw retaining sleeve 27. Pin 26 extends through holes 31 of the two jaws to provide a pivot. The end portions 32 of the jaws are hooked and have arcuate cut-outs 33 which closely embrace the base of the tapered end of the rod.

While I have illustrated and described several embodiments of my invention, it will be understood that these are by way of illustration only, and that various changes and modifications may be made within the contemplation of my invention and within the scope of the following claim.

I claim:

In combination with a drill bit having a tapered end, an extension rod having a U-shaped end and a threaded rod portion immediately adjacent thereto, a separate pair of opposing clamping jaws having portions contained between the leg portions of said U-shaped end which have registering holes, a pin extending through the leg portions of said U-shaped end and through said holes to provide a pivot for said jaws, the inner surfaces of said jaws and of said U-shaped end being tapered outwardly to correspond to the taper of said tapered end of the drill bit, the extremities of said jaws being hooked radially inwardly of said bit and having arcuate surfaces closely embracing the base portion of said tapered end, a jaw re- References Cited by the Examiner taining sleeve surrounding said jaws and 'U -shaped end, UNITED STATES PATENTS and a knurled nut having internal threads which threaded- 1y engage said threaded rod portion so that when the nut 54,990 5/66 Wlmmer 279-37 is turned, said jaws are pulled inwardly of said sleeve and 5 1 g s b th 't '11 t' htl l' e an y cammmg actlon erewl 11 W1 s y grasp a Y 111 2,193,917 3/40 Bone 279 89'1 drical portion of said bit immediately adjacent the base of said tapered end of the bit so as to act as a stop to prevent turning or pulling out of said bit from said jaws. ROBERT RIORDON Pr'mary Examiner 

